1. Field of the Invention
The present invention relates to a ligator used to knot a ligature in a body in a medical care, i.e., surgery, especially endoscopic surgery.
2. Description of the Related Art
A technique to make an incision portion smaller in surgery is regarded as important in order to accelerate the course of convalescence after an operation and make an operative wound left in a body smaller. Recently, endoscopic surgery permitting to make an incision portion excessively smaller has widely been put into practical use.
In such endoscopic surgery, there is required an operation to carry out ligation of tissue or a blood vessel in a body with the use of a ligature or to knot the ligature after suture to fix the sutured portion by an operator through a minor opening of an incision of the body. A medical appliance called a xe2x80x9cligatorxe2x80x9d has conventionally been used to achieve such an operation of knotting the ligature in the body from outside thereof. Japanese Provisional Publication No. HEI 05-317321 discloses one of examples of such a conventional ligator, which is illustrated in FIGS. 21 and 22. FIG. 21 is a schematic descriptive view of the conventional ligator and FIG. 22 is a cross-sectional view of essential elements of the conventional ligator.
The conventional ligator 100 as shown in FIGS. 21 and 22 comprises a handle 101 having a prescribed length, a recess portion 102 formed on the front end of the handle 101, a guide passage 103 provided so as to communicate with the recess portion 102 and extend beyond the bottom of the recess portion 102 between the opposite portions thereof toward the front end of the handle 101.
Description will be given below of a ligation operation using the conventional ligator 100. A ligature 50 is previously put around a target part in a body, which is to be subject to a ligation operation (i.e., tissue in the body, a blood vessel, or the like) (hereinafter referred to as the xe2x80x9ctarget regation part in the bodyxe2x80x9d) and the opposite ends of the ligature 50 are pulled out of the body with the use of another medical appliance. An operator crosses the opposite ends of the ligature 50 to make a half hitch 51 outside the body. Opposite portions of the ligature 50 extending from the half hitch 51 are put in the guide passage 103 in the vicinity of the recess portion 102. The operator moves the ligator 100 forward while holding the opposite ends of the ligature 50. As a result, the half hitch 51 shifts to move together with the front end of the ligator 100, while the ligature 50 smoothly slips in the guide passage 103 without occurrence of contact of the half hitch 51 with the recess portion 102 of the ligator 100. The ligator 100 is inserted into the body in such a state to move the half hitch 51 toward the target regation part in the body. After the half hitch 51 finally moves to the above-mentioned target part in the body, the opposite ends of the ligature 50 are pulled from outside the body to make a knot, while keeping the ligator 100 stationarily, thus providing a ligation condition for the target part in the body.
In the conventional endoscopic surgery, a port is used to be fixed to the surface of a body to facilitate insertion of a medical appliance such as the ligator into the body and removal of it from the body (see FIG. 1). A closed-type port, which is used in the endoscopic surgery according to aeroperitoneum, has a built-in valve for preventing occurrence of a gas leakage. A ligature that is put around a target part in the body, which is to be subject to a ligation operation, and pulled out of the body, comes into contact with the valve, resulting in a bending state in the middle of the ligature. When the ligator 100 is inserted into such a port, the ligature may come off the guide passage 103 at one of the opposite portions between which the recess portion 102 is placed, due to the bending state of the ligature in the vicinity of the valve. This may cause the half hitch 51 to deviate from the recess portion 102, deteriorating slidability of the ligature 50 and causing a problem. When the ligator 100 opens the valve and enters the port, a resistance force having a function of returning the valve to close it is applied to the ligator 100. An operator cannot easily recognize that such a resistance force is generated due to deviation of the half hitch 51 of the ligature or returning action of the valve. This makes it unable to judge properly whether the operation be continued or not, causing the other problem.
In case where the operator continues to insert the ligator 100 without recognizing deviation of the half hitch 51 of the ligature 50, the ligature 50 may be broken or an excessively large force may be applied to the target regation part in the body, around which the ligature 50 has been put, thus causing damage. When the ligature 50 comes off the front end of the ligator 100 within the port, it is very difficult to put again the ligature 50 on the front end thereof due to impossibility of visual inspection of the inside of the port.
The conventional ligator 100 has a non-uniform thickness. There exists a relatively large gap between the port into which the maximum thickness portion of the ligator 100 can be inserted and the ligator 100 has actually been inserted into the port. This may cause an aeroperitoneum gas to leak out during operation, thus making it impossible to ensure a proper field of vision through an endoscope, resulting in interruption of operation.
An object of the present invention, which was made to solve the above-described problems, is therefore to provide a ligator, which prevents a ligature from coming off the front end of the ligator, has a shape of the front end thereof, by which the ligature can easily be put on the front end of the ligator even when it comes off, permits to shift surely a half hitch of the ligature toward a target part, which is to be subject to a ligation operation, and permits an operator to carry out the ligation operation so as to improve remarkably an operation efficiency, thus reducing a burden of both the operator and a person to be operated.
In order to attain the aforementioned object, a ligator of the present invention comprises a ligation member formed of a bar-shaped body having a constant thickness in a region extending by at least a prescribed length from one end of said ligation member; a front hole formed on one end surface of said ligation member, said front hole having a prescribed shape and a prescribed depth in a longitudinal direction of said ligation member; and a pair of side holes formed on opposite positions at one end portion of said ligation member so as to be substantially at right angles to said front hole, said front hole being located between said opposite positions, and said side hole communicating with said front hole, opposite ends of a ligature to be knotted passing through said front hole and said side hole. In the feature of the present invention, the bar-shaped ligation member is provided on its front end with the front hole and the side holes. An operator passes the opposite ends extending from a half hitch of a ligature through the front hole and the side holes so that the half hitch is placed within the front hole. The operator carries out a ligation operation while holding the opposite ends of the ligature. When the ligator is inserted into a body, the side holes urge the ligature to shift the half hitch of the ligature into the body, while keeping the half hitch within the front hole of the ligator. When the ligator is pulled out of the body, the ligature comes into contact with the ligation member within the front hole and the side holes to hold securely the ligature. It is therefore possible to pass the ligator through a port to carry out the ligation operation without causing deviation of the half hitch and slip-off of the ligature. In addition, the half hitch of the ligature shifts together with the front end of the ligator to prevent an excessively large force from being applied to the target part, which is to be subject to the ligation operation, thus improving safety. The ligation member is provided with a portion to be inserted into the body, which has a shape with substantially a constant thickness in the longitudinal direction of the ligation member. As a result, it is possible to make an opening of the port smaller, thus permitting to reduce a gas leakage ratio upon operation according to aeroperitoneum.
In the present invention, said ligation member may be provided, as an occasion demands, with a pair of recesses each connecting smoothly an inner surface of each of said side holes of said ligation member and an outer surface of said ligation member, each of said recesses being formed by chamfering an edge portion from said inner surface to said outer surface toward an other end of said ligation member. In such a feature of the present invention, the ligation member is provided with the recesses for connecting partially the outer surface of the ligation member and the inner surface of the side holes. A ligature received in the side hole is guided into the recess to reach the outside of the ligator, thus preventing the ligature from coming easily off the recess to secure a proper receiving state of the ligature within the side hole. The ligature does not come off the front end of the ligator so long as an operator holds the opposite ends of the ligature. In addition, when the ligator is inserted into a body, the ligature can smoothly move through the side hole toward the outside of the ligator, thus reducing contact resistance of the ligature with the ligation member. Accordingly, it is possible to carry out an insertion operation of the ligator in the body without causing slack of the ligature.
The ligation member of the present invention may be provided, as an occasion demands, with a gap portion, which causes said front hole to communicate with said side holes, said gap portion being formed by cutting a prescribed portion out of said ligation member, which faces said front hole and said side holes formed at the one end portion said ligation member and extends from the inner surface to the outer surface, said gap portion permitting said ligature to be received in said front hole and said side holes or removed therefrom. In such a feature of the present invention, the ligation member is provided at its one end portion with the gap portion through which the front hole and the side holes communicates with each other and these holes also communicate with the outside. Accordingly, it is possible to insert the ligature into the front hole and the side holes through the gap portion and to remove the ligature from these holes through the gap portion. It is therefore possible to carry out effectively an operation for inserting the ligature into the front hole and the side holes before starting a ligation operation as well as the other operation for removing the ligature from these holes after the completion of the ligation operation. As a result, a period of time required for the ligation operation can be reduced, and a burden of both the operator and a person to be operated upon can also be reduced.
The ligation member of the present invention may be formed, as an occasion demands, into a cylindrical shape having a hollow portion in said region extending by said at least prescribed length, said hollow portion forming said front hole. In such a feature of the present invention, the ligation member is formed into the hollow cylindrical shape in at least prescribed region so that the front hole is formed as a cylindrical space and the cross-section of the portion to be inserted into a body through the conventional port provides a symmetric shape. This makes it possible to reduce the gap between the port and the ligation member, thus permitting to reduce remarkably a gas leakage ratio upon operation according to aeroperitoneum.
In the ligator of the present invention, said gap portion may be formed, as an occasion demands, by cutting partially out of a peripheral portion of said ligation member, which comes into contact with said front hole and extends from one of said side holes to another of said side holes, and then removing at least a part of an end peripheral portion of said ligation member, which is placed along said peripheral portion thus cut, thereby said end peripheral portion forming a pair of arcuate projections. In such a feature of the present invention, the gap portion extends from the one side hole to the other side hole and further extends from the middle between the side holes to the one end surface of the ligation member so as to form a T-shape. As a result, the ligation member is provided on its one end portion with a pair of projections, which are defined by the gap portion, the front hole and the side holes. An operator can have the ligature caught by one or both of the projections before carrying out a ligature-insertion operation to obtain a state in which the ligature can be received in the front hole and the side holes. It is therefore possible to facilitate passing the ligature through the front hole and the side holes by handling of the ligator. It is therefore possible not only to carry out effectively an operation for inserting the ligature into the front hole and the side holes before starting a ligation operation as well as the other operation for removing the ligature from these holes after the completion of the ligation operation, but also to receive the ligature into the respective holes formed on the front end portion of the ligation member or remove it therefrom in a desired manner during a knot operation in the body, so as to make easily and appropriately an elaborate and ingenious operation, thus improving remarkably the operation efficiency in the body.
In the ligator of the present invention, there may be adopted, as an occasion demands, a structure in which said front hole extends beyond a position of each of said side holes by a prescribed length toward the other end side of said ligation member; and said ligator further comprises an inner tube, which is formed of a tubular member having a prescribed cross-section, which can be inserted into said front hole, said inner tube being slidably received in said front hole in the longitudinal direction of said ligation member from a position in which a front end of said tubular member is placed beyond said gap portion to reach the other end side of said ligation member to another position in which said tubular member closes at least a part of said gap portion from said front hole side to prevent said ligature received in said side holes from coming off said side holes through said gap portion. In such a structure of the present invention, the inner tube is provided in the front hole so as to be slidable in the longitudinal direction of the ligation member within a prescribed range. As a result, there can be selected any one of a number of modes, i.e., one mode in which the inner tube is moved to open the gap portion through operation of the operator so that the ligature-insertion or removal operation is permitted through the gap portion, and the other mode in which the inner tube is moved to close partially the gap portion so that any ligature-insertion or removal operation is not permitted. It is therefore possible to control the ligature to come in or out of the ligation member through the gap portion. This makes it possible to insert the ligator into the body and cause it to approach a target part in the body, to which is to be subject to a ligation operation, while preventing completely the ligature from coming off the gap portion. Accordingly, efficiency of an insertion operation of the ligator into the body can be remarkably improved, while maintaining an easy operation for inserting the ligature into the front hole and the side holes, thus remarkably reducing an operational burden of the operator.
In the ligator of the present invention, there may be adopted, as an occasion demands, a structure in which said ligation member is provided at said one end portion of said ligation member with two portions facing tip end portions of said pair of arcuate projections through said gap portion, at least one of said two portions having another recess connecting smoothly a prescribed portion of an end surface of said ligation member facing said gap portion and the outer surface of said ligation member, said other recess being formed by chamfering said prescribed portion of said end surface of said ligation member toward the outer surface of the other end side of said ligation member. In such a feature of the present invention, there is provided the other recess connecting partially the prescribed portion of the end surface of said ligation member facing said gap portion and the outer surface of said ligation member. When the ligature is brought into contact with the ligation member so as to be placed along the other recess portion, force having a function of pulling the ligature into the front hole is applied to the ligature, providing a state in which the ligature can easily be caught by the projection. Even when the ligature comes off the gap portion of the ligation member so as to be away from the ligation member in the body, the ligature can easily be caught by the projection to lead the ligature into the gap portion through operation of the operator, so as to return a proper state in which the ligature is received in the front hole and the side holes. It is therefore possible to carry out consecutively an operation for knotting the ligature in the body in an appropriate manner when the ligator is once inserted into the body. There is required no operation for inserting the ligator into the body and removing it therefrom several times to receive the ligature in the front hole and the side holes, permitting to smooth progress of the ligation operation without taking much time, thus remarkably reducing an operational burden of the operator.
The ligator of the present invention may further comprise, as an occasion demands, an opening or closing member, which is mounted on to said ligation member, said opening or closing member being movable to a position in which a part of said opening or closing member fits into said gap portion to close at least a part of said gap portion to prevent said ligature received in said side holes from coming off said side hole through said gap portion. In such a feature of the present invention, the opening or closing member is mounted movably on the ligation member so that there can be selected any one of a number of modes, i.e., one mode in which the opening or closing member is moved to open the gap portion through operation of the operator so that the ligature-insertion or removal operation is permitted through the gap portion, and the other mode in which the opening or closing member is moved to close the gap portion so that any ligature-insertion or removal operation is not permitted. It is therefore possible to insert the ligator into the body and cause it to approach a target part in the body, to which is to be subject to a ligation operation, while preventing completely the ligature from coming off the gap portion. Accordingly, efficiency of an insertion operation of the ligator into the body can be remarkably improved, while maintaining an easy operation for inserting the ligature into the front hole and the side holes, thus remarkably reducing an operational burden of the operator.